Effects of calcium channel blockers on cellular apoptosis: implications for carcinogenic potential

Lercanidipine alleviates doxorubicin-induced lung injury by regulating PERK/CHOP and Bax/Bcl 2/Cyt c pathways

Doxorubicin (DOX), which is used to treat various cancers and hematological malignancies, has limited therapeutic application due to its toxicity in tissues and organs. These toxic effects occur through alterations in intracellular calcium regulation, elevated cell stress and oxidative damage, and increased apoptosis. Lercanidipine (LRD) is a long-acting antihypertensive calcium channel blocker with anti-inflammatory, anti-apoptotic, and antioxidant effects. The aim of this study was to investigate the effect of LRD on DOX-induced lung toxicity. Four groups (control, DOX, DOX + 0.5 LRD, and DOX + 2 LRD) totaling 32 rats were established. TNF-α levels in the lung tissues were detected by immunohistochemistry, and the tissues were subjected to histopathological examination. In determining oxidative stress, total antioxidant status (TAS) and total oxidative stress (TOS) were determined using spectrophotometry, and the oxidative stress index (OSI) value was calculated. The mRNA relative expression levels of the genes were evaluated by RT-qPCR. It was determined that inflammatory and oxidative stress markers and pro-apoptotic gene levels were increased and anti-apoptotic gene levels were decreased in the lung tissues of the DOX-administered group. In addition, histopathological changes were significantly increased. Although it was not statistically significant, inflammation, oxidative stress, and apoptosis were reduced, as were other histopathological indicators, in the group that received LRD (0.5 mg/kg). Inflammation, oxidative stress, and apoptosis were found to be statistically reduced and corroborated by histological findings in the group given LRD (2 mg/kg). In conclusion, it was determined that LRD had an ameliorative effect on DOX-induced lung toxicity in an experimental animal model.

Calcium signaling: A therapeutic target to overcome resistance to therapies in cancer

Innate and acquired resistances to therapeutic agents are responsible for the failure of cancer treatments. Due to the multifactorial nature of resistance, the identification of new therapeutic targets is required to improve cancer treatment. Calcium is a universal second messenger that regulates many cellular functions such as proliferation, migration, and survival. Calcium channels, pumps and exchangers tightly regulate the duration, location and magnitude of calcium signals. Many studies have implicated dysregulation of calcium signaling in several pathologies, including cancer. Abnormal calcium fluxes due to altered channel expression or activation contribute to carcinogenesis and promote tumor development. However, there is limited information on the role of calcium signaling in cancer resistance to therapeutic drugs. This review discusses the role of calcium signaling as a mediator of cancer resistance, and assesses the potential value of combining anticancer therapy with calcium signaling modulators to improve the effectiveness of current treatments.

Antihypertensive treatments and risks of lung Cancer: a large population-based cohort study in Hong Kong

BACKGROUND

There is a growing concern that the use of anti-hypertensives may be associated with an increased risk of cancer, but it remains uncertain for the association between anti-hypertensives and lung cancer risk, as well as their interaction with aspirin in chemoprotective effects.

METHODS

The goal of this study is to assess the association between anti-hypertensives use and the risk of lung cancer, as well as the chemopreventive impacts from the combination usage of aspirin and anti-hypertensives. A retrospective cohort study was conducted based on all the public hospital electronic medical records in Hong Kong. Patients with prescription records of anti-hypertensives (ACEi/ARB, CCB, β-blocker,α-blocker) and/or aspirin were included as the exposure groups. Using the Cox proportional hazards model with inverse probability weighting, we estimated hazard ratios (HRs) with 95% confidence intervals (CIs) for lung cancer risk from anti-hypertensives usage or combination usage of aspirin with anti-hypertensives. The likelihood ratio test and interaction model were adopted for exploring the interaction effects with aspirin.

RESULTS

A total of 6592 and 84,116 lung cancer cases were identified from the groups of anti-hypertensives users and anti-hypertensives users with aspirin, respectively. The group of non-aspirin patients who received anti-hypertensives showed a significantly lower risk of lung cancer (HR: 0.63, 95% CI: 0.60-0.66), compared to those without anti-hypertensives. When aspirin and α-blocker were used simultaneously, it could lower the risk of lung cancer significantly (HR: 0.53, 95% CI: 0.34-0.84). Moreover, the lower risk of lung cancer persisted with a longer follow-up period of anti-hypertensives usage. Combination usage with aspirin in the users of ACEi/ARB, CCB, and α-blocker showed significant interaction effects. However, the smoking effect could not be eliminated in this analysis.

DISCUSSION

Anti-hypertensive treatment was associated with a lower risk of lung cancer, which is associated with the anti-hypertensives exposure period. The potential interaction on the chemopreventive influence from combination usage of α-blocker and aspirin might exist. More corroborations on these findings are needed to focus on the different settings in future studies.

Calcium channel blockers in pancreatic cancer: increased overall survival in a retrospective cohort study

Repurposing commonly prescribed noncancer medications for use in oncology has substantial advantages over de-novo development of anticancer drugs. Calcium signalling has been implicated in many of the hallmarks of cancer. Previous in-vitro and in-vivo studies have shown that calcium channel blockers (CCBs) are able to promote apoptosis, inhibit proliferation and prevent invasion and metastasis in a variety of cancer types. This retrospective cohort study aimed to translate this into the clinic by investigating the effect of CCBs on survival in pancreatic cancer. One hundred sixty-four patients with unresectable pancreatic ductal adenocarcinoma were included. Data were collected on CCB prescription, and for a range of other potentially important prognostic factors: ECOG performance status, AJCC cancer stage, chemotherapy regimen, radiotherapy, age, hypertension and sex. Participants prescribed CCB (n = 30) were more likely to be older (P = 0.004) and have hypertension (P < 0.0005); baseline demographics were otherwise similar between groups. On adjusted cox regression patients prescribed CCBs demonstrated significantly improved overall survival; hazard ratio -0.496 (0.297-0.827; P = 0.007). Performance status (P < 0.0005), tumour stage (P < 0.0005), chemotherapy regimen (P < 0.0005), radiotherapy (0.002) and age (P = 0.012) were also independent predictors of survival. The Kaplan-Meier estimated median survival was 15.3 months for patients prescribed CCBs versus 10.1 months for patients not prescribed CCBs (P = 0.131). This study supports previous work suggesting CCBs may be beneficial in pancreatic cancer. Further work on larger datasets will allow for subgroup analysis delineating the effects of specific CCBs in combination with different forms of chemotherapy, paving the way for future prospective studies.

Hypertension is associated with oral, laryngeal, and esophageal cancer: a nationwide population-based study

Several studies have reported an association between hypertension and upper aerodigestive tract cancer, but no large-scale, population-based studies have been conducted to confirm this.The aim of this study was to explore the association between hypertension and risk of upper aerodigestive tract cancer in Koreans. Participants who underwent a national health screening examination from January 1 to December 31, 2009 (n = 9,746,606) were enrolled. We assessed the development of oral, laryngeal, or esophageal cancer until 2016 using records from the Korean Health Insurance claims database during the study period. During the seven-year follow-up period, 6,062, 2,658, and 4,752 subjects were newly diagnosed with oral, laryngeal, and esophageal cancer, respectively. Participants with metabolic syndrome had the highest risk of developing oral cancer (hazard ratio (HR) 1.09, 95% confidence interval (CI) 1.03-1.16), laryngeal cancer (HR 1.27, 95% CI 1.17-1.38), and esophageal cancer (HR 1.11, 95% CI 1.04-1.19). Hypertension was a remarkable risk factor for each cancer (HR 1.11, 95% CI 1.04-1.17 for oral cancer; HR 1.23, 95% CI 1.13-1.33 for laryngeal cancer; HR 1.25, 95% CI 1.18-1.33 for esophageal cancer) after adjusting for age and other variables including gender, smoking status, alcohol intake, exercise, body mass index, and diabetes. Patients with untreated hypertension were at highest risk of developing oral cancer (HR 1.15; 95% CI 1.05-1.26), laryngeal cancer (HR 1.25; 95% CI 1.09-1.44), and esophageal cancer (HR 1.47; 95% CI 1.33-1.63) after adjusting for confounders. Hypertension was associated with the risk of oral, laryngeal, and esophageal cancer, despite of the lack of detailed biochemical information including the cancer cell types (squamous cell carcinoma or adenocarcinoma), cancer stage, physical findings and other medical history. Further studies are warranted to determine the reasons for this association and to establish effective interventions in this vulnerable population.

Effects of Covalent Conjugates of Fullerene Derivatives with Xanthene Dyes on Activity of Ca2+-ATPase of the Sarcoplasmic Reticulum

The effects of the newly synthesized covalent conjugates of water-soluble fullerene derivatives (WSFD) with xanthene dyes: polyanionic WSFD-fluorescein (1), polycationic WSFD-fluorescein (2), polyanionic WSFD-eosin (3), and polyanionic WSFD (4), polycationic WSFD (5), fluorescein (6) and eosin (7), on activity of the membrane-bound Ca²⁺-ATPase of the sarcoplasmic reticulum (SR Ca²⁺-ATPase) were studied. Compounds 1, 3, 4, 6, and 7 inhibit the hydrolytic function of the enzyme, the inhibition constants for these compounds are Ki=1.3×10^-5 M (1), Ki=4.7×10^-6 M (3), Ki=2.5×10^-6 M (4), Ki=6.1×10^-5 M (6), and Ki=5.8×10^-6 M (7). The effects of compounds 3, 6, and 7 on the hydrolytic function of the enzyme is competitive; compounds 1 and 4 are noncompetitive. Polycationic WSFD fluorescein (2) and polycationic WSFD (5) do not affect ATP hydrolysis, but inhibit active Ca²⁺ transport in a concentration of 0.01 mM by 100±10 and 40±4%, respectively. Conjugates 1 and 3 completely inhibit the hydrolytic and transport functions of the enzyme in a concentration of 0.01 mM, and in a concentration of 0.001 mM inhibit active Ca²⁺ transport by 60±6 and 55±6% uncoupling the hydrolytic and transport functions of SR Ca²⁺-ATPases. The obtained results demonstrate a significant effect of the studied compounds on the active transmembrane transfer of Ca²⁺ and make it possible to predict the presence of antimetastatic and antiaggregatory activities of the studied compounds.

Calcium Channel Blocker Use and the Risk for Prostate Cancer: A Population-Based Nested Case-Control Study

INTRODUCTION

Calcium channels play a significant role in the regulation of cell proliferation and apoptosis. This study investigates associations between calcium channel blocker (CCB) use and the incidence of prostate cancer (PCa).

METHODS

A nested case-control study was conducted using the Clalit Health Services database. We formed a population-based cohort of patients who were prescribed their first antihypertensive agent between 2000 and 2014. For each newly diagnosed PCa case in the cohort, 10 controls were matched by age, calendar year of cohort entry, and duration of follow-up. Multivariate conditional logistic regression analyses were used to evaluate the odds ratios (ORs) of PCa among CCB users compared with users of other antihypertensive drugs.

RESULTS

We identified 4346 patients with newly diagnosed PCa during the median follow-up of 5.3 years. The exposure to CCBs was associated with a slight increase in risk for PCa (OR 1.10, 95% confidence interval [CI] 1.02-1.18) when compared with non-CCB antihypertensive drugs. In secondary analyses, evidence was found of a duration-response relationship, with the association for PCa increasing by 27% for every 10-year increment of CCB use (OR 1.27, 95% CI 1.04-1.56).

CONCLUSIONS

The results of this large population-based study indicate a modest but significant increase in the risk of PCa among CCB users, and the risk increases with duration of use.

Ion Channels: New Actors Playing in Chemotherapeutic Resistance

In the battle against cancer cells, therapeutic modalities are drastically limited by intrinsic or acquired drug resistance. Resistance to therapy is not only common, but expected: if systemic agents used for cancer treatment are usually active at the beginning of therapy (i.e., 90% of primary breast cancers and 50% of metastases), about 30% of patients with early-stage breast cancer will have recurrent disease. Altered expression of ion channels is now considered as one of the hallmarks of cancer, and several ion channels have been linked to cancer cell resistance. While ion channels have been associated with cell death, apoptosis and even chemoresistance since the late 80s, the molecular mechanisms linking ion channel expression and/or function with chemotherapy have mostly emerged in the last ten years. In this review, we will highlight the relationships between ion channels and resistance to chemotherapy, with a special emphasis on the underlying molecular mechanisms.

Calcium Channel Blockers and the Risk for Lung Cancer: A Population-Based Nested Case-Control Study

Background: It has been suggested that calcium channel blockers (CCBs) may increase the risk of lung cancer; however, current evidence is conflicting and limited. Objective: Investigate the associations between CCB use and lung cancer. Methods: We conducted a population-based nested case-control study. A cohort was formed of patients prescribed their first antihypertensive agent from 2000 to 2014. CCB exposure information was obtained by identification of all prescriptions dispensed during study follow-up. Cases were patients newly diagnosed with lung cancer during follow-up. Each case was matched with 10 controls by age, sex, calendar year of cohort entry, and duration of follow-up. Multivariate conditional logistic regression was used to estimate odds ratios (ORs) with 95% CIs of lung cancer associated with ever use of CCBs. Results: During a median follow-up of 6.2 years, we identified 4174 cases of lung cancer. Ever use of CCBs was associated with an increased risk of lung cancer (adjusted OR = 1.13; 95% CI = 1.06-1.21), when compared with the use of other antihypertensive drugs. A duration-response relation was observed, with the ORs gradually increasing with longer cumulative duration of CCB use (<5 years: OR = 1.12, 95% CI = 1.04-1.20; 5-10 years: OR = 1.22, 95% CI = 1.07-1.40; >10 years: OR = 1.33, 95% CI = 0.90-1.96; P trend < 0.001). Conclusion and Relevance: The results of this large population-based study indicate that the use of CCBs is associated with a modest but significant increase in the risk of lung cancer. This association appeared to increase with longer duration of use.

The Risk for Lung Cancer Incidence with Calcium Channel Blockers: A Systematic Review and Meta-Analysis of Observational Studies

INTRODUCTION

There are conflicting findings regarding the association between the use of calcium channel blockers (CCBs) and the risk of lung cancer. Considering the public health importance of lung cancer prevention, and emerging evidence of a significant biologic role of calcium channel regulation in the development of lung cancer, we conducted a meta-analysis to assess the risk of lung cancer in CCB users compared with non-CCB users.

MATERIALS AND METHODS

We conducted a comprehensive systematic search of leading medical databases for observational studies published up to December 2017 that examined CCB use and the risk of lung cancer. We used random-effects models to pool results. The impact of duration of CCB use on the estimated effect size was explored using random effects meta-regression.

RESULTS

Ten studies (six cohort and four case-control studies) that evaluated the overall cancer risk among 38,758 CCB users were included in the analysis. Overall risk ratio (RR) for CCB use and lung cancer was 1.15 (95% confidence interval [CI] 1.01-1.32). Subgroup analysis by duration of CCB use suggested that the observed increase in lung cancer risk was driven by the results of five studies with prolonged (≥ 4 years) exposure (RR 1.18; 95% CI 1.08-1.30).

CONCLUSIONS

Our analysis suggests exposure to CCBs is associated with an increased risk of lung cancer. Considering their widespread use, and the paucity of data on the long-term effects of chronic exposure to CCBs, these results are reason for concern and warrant further investigation.

SYSTEMATIC REVIEW REGISTRATION

The protocol for this study was registered at the PROSPERO registry of systematic reviews (registry number: CRD42017056362).

Systems Perturbation Analysis of a Large-Scale Signal Transduction Model Reveals Potentially Influential Candidates for Cancer Therapeutics

Dysregulation in signal transduction pathways can lead to a variety of complex disorders, including cancer. Computational approaches such as network analysis are important tools to understand system dynamics as well as to identify critical components that could be further explored as therapeutic targets. Here, we performed perturbation analysis of a large-scale signal transduction model in extracellular environments that stimulate cell death, growth, motility, and quiescence. Each of the model’s components was perturbed under both loss-of-function and gain-of-function mutations. Using 1,300 simulations under both types of perturbations across various extracellular conditions, we identified the most and least influential components based on the magnitude of their influence on the rest of the system. Based on the premise that the most influential components might serve as better drug targets, we characterized them for biological functions, housekeeping genes, essential genes, and druggable proteins. The most influential components under all environmental conditions were enriched with several biological processes. The inositol pathway was found as most influential under inactivating perturbations, whereas the kinase and small lung cancer pathways were identified as the most influential under activating perturbations. The most influential components were enriched with essential genes and druggable proteins. Moreover, known cancer drug targets were also classified in influential components based on the affected components in the network. Additionally, the systemic perturbation analysis of the model revealed a network motif of most influential components which affect each other. Furthermore, our analysis predicted novel combinations of cancer drug targets with various effects on other most influential components. We found that the combinatorial perturbation consisting of PI3K inactivation and overactivation of IP3R1 can lead to increased activity levels of apoptosis-related components and tumor-suppressor genes, suggesting that this combinatorial perturbation may lead to a better target for decreasing cell proliferation and inducing apoptosis. Finally, our approach shows a potential to identify and prioritize therapeutic targets through systemic perturbation analysis of large-scale computational models of signal transduction. Although some components of the presented computational results have been validated against independent gene expression data sets, more laboratory experiments are warranted to more comprehensively validate the presented results.

Commonly used diabetes and cardiovascular medications and cancer recurrence and cancer-specific mortality: a review of the literature

INTRODUCTION

Cancer most commonly arises in the elderly who are often burdened with comorbidities. Medications used for treating these comorbidities may alter cancer prognosis. Understanding the impact of these medications on cancer is important in order to make effective evidence-based decisions about managing comorbidities while improving cancer outcomes.

AREAS COVERED

The evidence on diabetes, statins, antihypertensive and anti-inflammatory medications and their association with cancer recurrence and cancer-specific mortality are reviewed. The strengths and limitations of the existing literature, the current state of the field and future directions are discussed.

EXPERT OPINION

Metformin and aspirin were associated with a reduced risk of cancer recurrence and cancer-specific mortality. The evidence for statins and antihypertensive medications on cancer survival was inconsistent. There were few studies to suggest that any of the medication classes of interest were associated with negative effects on cancer survival. Methodological shortcomings within observational studies, such as confounding, distinguishing between use of medications pre-cancer versus post-cancer diagnosis/treatment, misclassification of exposures/outcomes, informative censoring and competing risks, must be considered. New observational studies addressing these limitations are essential. Some clinical trials are underway to further investigate the beneficial effects of these drugs and completed trials have confirmed results demonstrated in observational studies.

Comparative safety of cardiovascular medication use and breast cancer outcomes among women with early stage breast cancer

Breast cancer tends to occur in an older age group of women also burdened with comorbidities such as cardiovascular disease (CVD). Numerous medications used to manage CVD (e.g., statins and antihypertensives) are hypothesized to alter breast cancer risk, but there are few studies on breast cancer outcomes. The COmmonly used Medications and Breast Cancer Outcomes (COMBO) cohort was developed to study how medications and co-morbidities influence breast cancer prognosis. Cohort study among adult women, diagnosed with incident early stage breast cancer, and enrolled in an integrated health plan. Data sources included health plan administrative databases, Surveillance, Epidemiology, and End Results tumor registry, and medical records. Statins, angiotensin-converting enzyme inhibitors (ACEI), beta blockers (BB), calcium blockers, and diuretics were the exposures of interest. The outcome was second breast cancer events (SBCE) defined as recurrence or second primary breast cancer. We used multivariable Cox proportional hazards models to estimate hazard ratios (HR) and 95 % confidence intervals (CI) for SBCE, and components of SBCE. 4,216 women were followed for a median of 6.3 years, and 13.2 % experienced a SBCE (first of: n = 415 recurrences and n = 143 s primary breast cancers). Compared to non-users, we observed an increased risk of second primary breast cancer with ACEI use (HR = 1.66; 95 % CI, 1.06-2.58) and an increased risk of recurrence with BB use (HR = 1.29; 95 % CI, 1.01-1.64). There was suggestion of a reduced risk of SBCE with statin use (HR = 0.82; 95 % CI, 0.62-1.08) and second primary breast cancer with BB use (HR = 0.77; 95 % CI, 0.50-1.19). No differences in outcomes were observed by duration of medication use. A majority of CVD medications evaluated in this study appear safe with respect to SBCE, but ACEI and BB use warrant further evaluation. The study presented is one example of the questions that can be addressed using the COMBO cohort.

Meta-analysis: risk of esophageal adenocarcinoma with medications which relax the lower esophageal sphincter

Reasons for the rising annual incidence of esophageal adenocarcinoma (EAC) remain uncertain. Previous studies have given conflicting results, but some have suggested that drugs which relax the lower esophageal sphincter (LES) may increase the risk of EAC. This study is to determine systematically the risk of EAC associated with individual medications which relax the LES and compare risks with esophageal squamous cell carcinoma (ESCC) and gastric cardia adenocarcinoma (GCA). Relevant published studies were identified by systematic searching PubMed for case-control studies reporting on risk of EAC, ESCC or GCA with use of medications known to reduce LES pressure. Pooled odds ratios (ORs) were calculated for each malignancy. Data were analyzed from four case-control studies involving 9,412 participants. EAC was significantly associated with theophylline use (OR 1.55, 95% confidence interval [CI] 1.05-2.28; P= 0.03, I(2) = 0%) and anticholinergic medications (OR 1.66, 95% CI 1.13-2.44; P= 0.01, I(2) = 84%). This effect was not observed in cases of ESCC or GCA. Other drug groups including calcium channel modulators and nitrates did not increase the risk of EAC. An inverse relationship was observed between ESCC and nitrates and between GCA and benzodiazepines. The lack of increased EAC risk with many commonly used medications is reassuring. However, a significant correlation was found between EAC and the use of anticholinergics and theophyllines. This may reflect common causality between obstructive lung disease and EAC, and further studies to explore these relationships are warranted.

Impact of metabolic factors on subsequent cancer risk: results from a large-scale population-based cohort study in Japan

The impact of metabolic factors, which are major risk factors for cardiovascular disease, on total cancer risk has not been clarified. We prospectively examined whether metabolic factors and their aggregates predict the subsequent occurrence of total and major sites of cancer in the Japan Public Health Center-based Prospective Study. A total of 27 724 participants (9548 men and 18 176 women) aged 40-69 years participating in a questionnaire and health checkup survey in 1993-1995 were followed for total cancer incidence through 2004. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated for metabolic factors and for two criteria of their aggregates (three or more than three factors and two or more than two additional factors in addition to being overweight) with a Cox proportional hazards model to control for potential confounding factors. In both sexes, the presence of metabolic factors in the aggregate did not predict subsequent occurrence of cancer as a whole. By site, a significant increase in risk was observed for male liver cancer [HR = 1.73, CI = 1.03-2.91 (three or more than three factors); HR = 1.99, CI = 1.11-3.58 (two or more than two additional factors in addition to being overweight)], and female pancreatic cancer [HR = 1.99, CI = 1.00-3.96 (two or more than two additional factors in addition to being overweight)]. For other sites, positive associations were observed only for specific metabolic factors, that is, high triglycerides and male colon cancer (HR = 1.71, CI = 1.11-2.62), and obesity and female breast cancer (HR = 1.75, CI = 1.21-2.55). Metabolic factors in the aggregate may have little impact on total cancer risk in the Japanese population, although the association between specific components and specific cancers suggests an etiologic link between them.

Use of common medications and breast cancer risk

Prescription and over-the-counter medications are widely used in the United States and many western countries. More than two-thirds of women ages >45 years, who are at greatest risk for breast cancer, take prescription medication. In light of the ubiquitous nature of medication use and the fact that breast cancer remains the most common cancer in women, research on the role of medication use in breast cancer etiology is warranted. We summarize the epidemiologic evidence on the association between breast cancer risk and use of common medications, including antibiotics, antidepressants, statins, antihypertensives, and nonsteroidal anti-inflammatory drugs. Overall, there is little evidence that would implicate the use of antibiotics, antidepressants, statins, and antihypertensives in the etiology of breast cancer. Although several prospective studies and a randomized low-dose aspirin chemoprevention trial have not shown lower risk of breast cancer among aspirin users, most studies that have examined the potential chemoprotective effect of nonsteroidal anti-inflammatory drugs have shown significant risk reductions for regular and prolonged use of these drugs. The existing literature on the role of medication use in breast carcinogenesis is complicated. Interpretation of the evidence is hampered due to major methodologic differences across studies, including exposure assessment, exposure classification, and adjustment for potential confounding variables. These differences largely stem from the fact that the majority of articles on this topic represent secondary data analyses from studies with inadequate information on exposure or confounders. Thus, future epidemiologic studies specifically designed to study these ubiquitous and biologically plausible exposures are warranted.

Prediction of prostate cancer using hair trace element concentration and support vector machine method

A change in the normal concentration of essential trace elements in the human body might lead to major health disturbances. In this study, hair samples were collected from 115 human subject, including 55 healthy people and 60 patients with prostate cancer. The concentrations of 20 trace elements (TEs) in these samples were measured by inductively coupled plasma-mass spectrometry. Asupport vector machine was used to investigate the relationship between TEs and prostate cancer. It is found that, among the 20 TEs, 10 (Mg P, K, Ca, Cr, Mn, Fe. Cu, Zn, and Se) are related to the risk of prostate cancer. These 10 TEs were used to build the prediction model for prostate cancer. The model obtained can satisfactorily distinguish the healthy samples from the cancer samples. Furthermore, the cross-validation by leaving-one method proved that the prediction ability of this model reaches as high as 95.8%. It is practical to predict the risk of prostate cancer using this model in the clinics.

In vitro growth inhibition of human colonic tumor cells by Verapamil

AIM: To investigate the effects and mechanisms of Verapamil on cultured human colonic tumor (HCT) cells.

METHODS: HCT cells were treated with different concentrations of Verapamil, and their proliferation was examined by MTT assay. The areas of sub-diploid peak were measured by flow cytometry, and the DNA ladder was found by agarose gel electrophoresis. The characteristic changes in morphology were observed under light microscopy. The cell nuclei (propidium iodide labeled, PI-labeled) and cellular distribution and concentration of calcium (Fluo-3-labeled) were studied by using laser confocal scanning microscope.

RESULTS: The proliferation of HCT cells was inhibited by different concentrations of Verapamil. With the increase in concentration of Verapamil, the percent of G0-G1 phase cells in HCT cells increased and that of S phase cells decreased. After treating with different concentrations of Verapamil, flow cytometry showed that HCT cells were enlarged in areas of sub-diploid in a dose-dependent manner. Gel electrophoresis results displayed a typical DNA ladder. On staining with Wrights-Giemsa, the typical cellular apoptosis morphologic changes were also observed. PI-labeled cell nuclei were found markedly changed. In addition, we inspected that the 100 μmol/L Verapamil could increase the intracellular calcium ion concentration [Ca²⁺]_i in HCT cells.

CONCLUSION: Verapamil can inhibit proliferation of HCT cells via inducing cell apoptosis.

HERG K+ channel expression-related chemosensitivity in cancer cells and its modulation by erythromycin

PURPOSE

Previous studies have found that the HERG K+ channel is highly expressed in some cancers. In the study reported here, we investigated HERG expression in various cancer cell lines, its correlation with chemosensitivity to vincristine, paclitaxel, and hydroxy-camptothecin, and its biochemical modulation.

METHODS

The MTT assay and clonogenic assay were used to detect the cytotoxicity of anticancer drugs in vitro. HERG expression was analyzed by Western blotting or immunocytochemistry. Gene transfection was used to examine the changes in HERG-related chemosensitivity. Cell cycle phase distribution was detected by flow cytometry and drug combinations were evaluated by the MTT assay.

RESULTS

HERG expression levels differed widely between various human cancer cell lines and HT-29 cells expressing high levels of HERG were more sensitive than A549 cells expressing low levels of HERG to vincristine, paclitaxel, and hydroxy-camptothecin. In terms of IC50, the chemosensitivities of herg-transfected A549 cells to vincristine, paclitaxel and hydroxy-camptothecin were significantly increased. However, for cisplatin and 5-fluorouracil, no significant difference between herg-transfected A549 cells and parent A549 cells was detected. Erythromycin, a HERG K+ channel blocker, suppressed the growth of various cancer cells and the potency was correlated with HERG expression levels. Combinations of erythromycin and vincristine, paclitaxel or hydroxy-camptothecin showed synergy in cytotoxicity to HT-29 cells. Erythromycin also enhanced the G2/M arrest induced by vincristine in HT-29 cells. There were synergistic effects between erythromycin and vincristine, paclitaxel, and hydroxy-camptothecin, and chemosensitivity was correlated with HERG expression level.

CONCLUSIONS

HERG expression levels and chemosensitivity were positively correlated for vincristine, paclitaxel, and hydroxy-camptothecin. Erythromycin was active as a modulator. These results suggest that HERG may serve as a molecular marker and modulating target for individualized cancer therapy.

Inverse association between prostate cancer and the use of calcium channel blockers

Calcium channel blockers block calcium signal-mediated apoptosis. It is hypothesized that the use of these drugs may be associated with the development of cancer. This study investigated the association between daily use of calcium channel blockers and prostate cancer in a community-based cohort of men who participated in a longitudinal study of lower urinary tract symptoms. Study subjects were men ages 40 to 79 years by January 1, 1990, and were randomly selected from Olmsted County in Minnesota. At baseline, participants underwent an interview to determine all medications taken on a daily basis, including calcium channel blockers and to elicit a family history of prostate cancer. During follow-up, all men with a histological diagnosis of prostate cancer were identified through patient self-report and by a review of the complete medical record. Over 12,668 person years of follow-up, 15 (6.8%) of 220 calcium channel blocker users and 120 (10.5%) of 1142 nonusers developed prostate cancer (P = 0.09; odds ratio, 0.62; 95% confidence interval, 0.36-1.10). With adjustment for age and family history of prostate cancer, the risk (odds ratio, 95% confidence interval) of prostate cancer was 0.55 (0.31-0.97) in calcium channel blocker users compared with nonusers. In analyses stratified by family history of prostate cancer, the risk of prostate cancer was 0.45 (0.23-0.88) in men without a family history and 2.64 (0.82-8.47) in men with a family history of prostate cancer (P = 0.006). These findings suggest an association between prostate cancer and daily use of calcium channel blockers that varies by family history of prostate cancer.

Targeting mediators of vascular injury in scleroderma

Increasing evidence suggests that the vasculopathy of scleroderma is mediated by a number of soluble factors and involves a complex interaction between endothelial cells, smooth muscle cells, extracellular matrix, intravascular coagulation factors, and circulating cells. Novel therapeutic approaches beyond vasodilator therapy are being developed by recognizing important molecular pathways involved in scleroderma vascular disease. The success of this strategy is most evident in pulmonary hypertension, an often fatal complication of scleroderma. In this article, the authors explore therapies for scleroderma that target endothelial cells, smooth muscle cells, reactive oxygen species, and circulating blood cells. The authors highlight clinical trials that have investigated the role of prostacyclin (and its analogues) and bosentan in managing scleroderma-related pulmonary hypertension. Finally, the authors look at the potential role of biomarkers as surrogate indicators of active vascular disease in scleroderma.

Functional decline in aging and disease: a role for apoptosis

The process of aging and senescence is associated with a decline in several organ functions and ultimately takes away independence and reduces quality of life. The precariously marginal functional reserves of the immune, pulmonary, and cardiovascular systems are among the most important causes of increased hospitalization in the older population. When complicated by chronic diseases, as is often the case, the problem is magnified. Apoptosis, or programmed cell death, is a process that goes on continuously throughout life. It is involved in embryogenesis for proper organ and tissue development. After birth and through adulthood, it helps eliminate unneeded and damaged cells. There is evidence that advanced age is associated with dysregulation of apoptosis. Several studies have shown age-related changes in the levels of proteins and factors that regulate apoptosis. This could explain the age-associated increased prevalence of cancers, certain autoimmune diseases, and neurodegenerative disorders in older people. More studies are needed to further elucidate the process of apoptosis. With this knowledge, the use of gene therapy and apoptosis modulators may someday have therapeutic value in preventing the functional decline we see in the older population.

2-Methoxyestradiol-induced caspase-3 activation and apoptosis occurs through G(2)/M arrest dependent and independent pathways in gastric carcinoma cells

BACKGROUND

2-Methoxyestradiol (2-Me), one of the estrogen metabolites, has recently been found to possess anti-angiogenesis activity in vivo. Many chemotherapeutic agents, such as taxol, docetaxel, and vinblastine, interact with microtubules and then induce apoptosis. It has been suggested that 2-Me acts on microtubules and results in G(2)/M-cycle arrest of tumor cells. Whether 2-Me induces apoptosis in gastric carcinoma cell lines is not known. Moreover, reactive oxygen species (ROS) produced by 2-Me may be involved in cytotoxicity of tumor cells. Thus, another objective of this study was to evaluate the relation between cell cycle arrest, ROS formation, and caspase activity levels after 2-Me treatment in gastric carcinoma cells.

METHODS

It was determined whether 2-Me directly induced apoptosis in two gastric carcinoma cell lines (SC-M1 and NUGC-3) through caspase-3 and caspase-8 activation and, eventually, induced DNA fragmentation. To clarify the effect of 2-Me-induced G(2)/M arrest in apoptosis, calcium ionophore, A23187, and thapsigargin were used to modulate 2-Me-induced cell cycle responses. Moreover, the role of 2-Me-induced ROS formation in the cell cycle responses also was evaluated.

RESULTS

It was found that 2-Me treatment resulted in G(2)/M-cycle arrest, caspase-8 and caspase-3 activation, and DNA fragmentation. In addition, the 2-Me induced, concomitant increases of peroxide and superoxide anions were correlated with G(2)/M-cycle arrest. Treatment with calcium ionophore A23187 and thapsigargin partially reversed the 2-Me-induced G(2)/M-cycle arrest, with a concomitant decrease in both peroxide and superoxide levels. Moreover, A23187 blocked the 2-Me-induced caspase-3 activation, whereas thapsigargin had no effect. Treatment with calcium channel blockers did not affect 2-Me-induced cell cycle arrest or caspase-3 activation.

CONCLUSIONS

These results suggest that the 2-Me-induced apoptosis of gastric carcinoma cells by DNA fragmentation accompanied caspase activation. Elevation of free radicals was associated with G(2)/M-cycle arrest. The induction of G(2)/M-cycle arrest is not a prerequisite for caspase activation.

Calcium channel blockers in the management of preterm labor and hypertension in pregnancy

Calcium channel blockers (CCBs) have the ability to inhibit contractility in smooth muscle cells. CCBs have an already established role in the treatment of non-pregnant hypertension and angina pectoris. Some epidemiological studies found an association between the use of CCBs and an increase in cardiovascular mortality, malignancy, and gastrointestinal bleeding. More recent studies with many more patients and a longer follow-up did not find these associations. In obstetrics CCBs have become increasingly popular for the management of preterm labor and pregnancy-induced hypertensive disorders. Meta-analysis shows that use of nifedipine in comparison with betamimetics is associated with a more frequent successful prolongation of pregnancy in case of preterm labor, resulting in significantly fewer admissions of newborns to the neonatal intensive care unit (NICU), and is associated with a lower incidence of respiratory distress syndrome. No adverse fetal side effects in humans have been reported with the use of nifedipine for obstetric indications. Nifedipine is an effective and safe drug to use when tocolytic therapy is indicated for preterm labor. In preeclampsia nifedipine effectively lowers blood pressure and can be a good alternative for (di) hydralazine.

2-Methoxyestradiol-induced caspase-3 activation and apoptosis occurs through G(2)/M arrest dependent and independent pathways in gastric carcinoma cells

BACKGROUND

2-Methoxyestradiol (2-Me), one of the estrogen metabolites, has recently been found to possess anti-angiogenesis activity in vivo. Many chemotherapeutic agents, such as taxol, docetaxel, and vinblastine, interact with microtubules and then induce apoptosis. It has been suggested that 2-Me acts on microtubules and results in G(2)/M-cycle arrest of tumor cells. Whether 2-Me induces apoptosis in gastric carcinoma cell lines is not known. Moreover, reactive oxygen species (ROS) produced by 2-Me may be involved in cytotoxicity of tumor cells. Thus, another objective of this study was to evaluate the relation between cell cycle arrest, ROS formation, and caspase activity levels after 2-Me treatment in gastric carcinoma cells.

METHODS

It was determined whether 2-Me directly induced apoptosis in two gastric carcinoma cell lines (SC-M1 and NUGC-3) through caspase-3 and caspase-8 activation and, eventually, induced DNA fragmentation. To clarify the effect of 2-Me-induced G(2)/M arrest in apoptosis, calcium ionophore, A23187, and thapsigargin were used to modulate 2-Me-induced cell cycle responses. Moreover, the role of 2-Me-induced ROS formation in the cell cycle responses also was evaluated.

RESULTS

It was found that 2-Me treatment resulted in G(2)/M-cycle arrest, caspase-8 and caspase-3 activation, and DNA fragmentation. In addition, the 2-Me induced, concomitant increases of peroxide and superoxide anions were correlated with G(2)/M-cycle arrest. Treatment with calcium ionophore A23187 and thapsigargin partially reversed the 2-Me-induced G(2)/M-cycle arrest, with a concomitant decrease in both peroxide and superoxide levels. Moreover, A23187 blocked the 2-Me-induced caspase-3 activation, whereas thapsigargin had no effect. Treatment with calcium channel blockers did not affect 2-Me-induced cell cycle arrest or caspase-3 activation.

CONCLUSIONS

These results suggest that the 2-Me-induced apoptosis of gastric carcinoma cells by DNA fragmentation accompanied caspase activation. Elevation of free radicals was associated with G(2)/M-cycle arrest. The induction of G(2)/M-cycle arrest is not a prerequisite for caspase activation.

The effect of enalapril and verapamil on the left ventricular hypertrophy and the left ventricular cardiomyocyte numerical density in rats submitted to nitric oxide inhibition

Forty male Wistar rats were separated into four groups of ten rats each (control and other three groups that have received nitric oxide (NO) synthesis inhibitor L-NAME) but the last two groups have concomitantly received antihypertensive drugs (Enalapril and Verapamil). After 40 days of experimentation, the heart and the ventricles were measured. The optical disector was used for the calculation of numerical density of the cardiomyocytes (Nv[c]). The left ventricular myocytes number (N[c]) was calculated as the product of Nv[c] and the left ventricular myocardium volume (LVMV) that was determined by using the Scherle's method. In the L-NAME group the blood pressure (BP) had a significant weekly increment. In the enalapril and the verapamil groups, BP increased in the first two weeks, but decreased in the following weeks. The LVMV increased in the L-NAME rats and decreased in the enalapril and verapamil animals. The Nv[c] and N[c] decreased in the L-NAME rats but the verapamil and enalapril treatments maintained the Nv[c] close to the control group. In conclusion, the left ventricular hypertrophy and the significant decrease of the left ventricular cardiomyocyte number caused by the NO synthesis inhibition are efficiently prevented with the use of enalapril and verapamil.

Cancer risk and mortality in users of calcium channel blockers. A cohort study

BACKGROUND

Data regarding the association between the use of calcium channel blockers and cancer risk have been conflicting. In the current study, the authors examined the cancer risk and mortality in users of calcium channel blockers in North Jutland County, Denmark.

METHODS

The authors conducted a cohort study using record linkage between a population-based prescription database, the Danish Cancer Registry, and the Danish Death Registry including 23, 167 users of calcium channel blockers who received >/=2 prescriptions between January 1, 1989 and December 31, 1995. The authors calculated the standardized incidence ratios and standard mortality ratios for cancer, along with corresponding 95% confidence intervals (95% CI).

RESULTS

Overall, 967 incident cases of cancer occurred, resulting in a standardized incidence ratio of 1.04 (95% CI, 0.98-1.11). There was a slightly elevated nonsignificant risk of tobacco-related cancer. No increased risk of breast or colon carcinoma was observed. The cancer mortality was close to that expected in the background population (standardized mortality ratio of 0.97; 95% CI, 0.89-1.04).

CONCLUSIONS

This large-scale, population-based cohort study adds to the increasing evidence indicating no substantial association between the use of calcium channel blockers and the incidence rate of cancer or cancer mortality.